Rotabolt Ltd. has launched what it says is the world’s first safety bolt that constantly monitors tension across a bolted joint and gives a clear visual indication, the Vision.
Maintained tension is critical to the safety of bolted joints, and unlike the traditional tools and methods of bolt tightening, which according to Rotabolt do not measure the tension across the joint, the Vision gives a constant and accurate tension measurement. It is easy to fit and to monitor and is cost effective as it brings major savings in maintenance costs, the company says.
The new bolts operate on the same internal air-gap technology as the original Rotabolt, but instead of a “finger check,” a special cap on the head of the bolt, the Rotabolt Vision has a specially developed visual indicator, which appears as an unbroken yellow line across the head of the bolt. As soon as any tension is lost across the bolt, the indicator rotates 90° to show a distinct right angle break in the yellow line. The indicator can be seen from up to 25 m away and for difficult locations, such as oil rigs or complex installations, which are not readily accessible, the joints can easily be checked by binocular.
Sparrows Offshore has installed the Rotabolt Vision on one of the cranes on the Marathon Oil UK Brae Bravo platform in the North Sea. The company fitted the Vision bolts on the connecting flanges of the main A frame in September 2003.
“The Vision bolts have performed very well. We have had no problems,” Sparrows Offshore Project Engineer, Stephen Gowans, says. “Within one hour, we can carry out an ‘eyeball check’ of all the bolts on the A frame of the crane. Previously, with a standard bolt, this is an operation that would have taken us all day.”
Sparrows Offshore is now looking to fit the Rotabolt Vision to the boom flanges as the next progression.
